Study Shed New Light on Brain’s Decision-making Process
New research reveals the complex circuits involved in regulating the neurotransmitter dopamine in our brains. Traditionally thought to be limited to reward seeking, the new study shows that parts of the ‘emotional’ brain may also manipulate dopamine to help us pay attention and react to new information in the environment.
The study, which appears in the journal Neuropsychopharmacology, was led by Julie Fudge, M.D., with the University of Rochester Medical Center (URMC) Department of Neuroscience.
The research focuses on an area of the brain called the amygdala, which is known to be important for social and emotional development and behaviors. The amygdala receives sensory information – sight, sound, and smells – and processes it by combining it with information stored in our memories. It evaluates changes or new information to help determine whether it is worthy of our attention or if it can be ignored. The new study shows that one way the amygdala can accomplish this is by communicating with the brain’s dopamine producing cells.
The neurons responsible for producing dopamine are increasingly being recognized as a diverse group. While these cells have long been known to play a role in reward seeking, our understanding of their function is changing. While some dopamine neurons are involved in responding to positive stimulus, others fire in response to negative cues, and others are activated depending upon whether or not the brain believes the new information is relevant.
The new research was conducted in animals and shows that the amygdala – which has a direct line of communication into the part of the brain that contains dopamine neurons – triggers specific dopamine cells using a ‘stress’ peptide known a corticotropin releasing hormone. These cells, in turn, project to a region of the brain called the striatum which is known to encode decision-making and planning strategies.
Taken together, the findings suggest that the amygdala plays an important role in communicating information about ‘uncertain’ environmental change to dopamine neurons that cause the individual to pay attention and prepare to take action.
This study not only broadens understanding of how the brain interprets and responds to the world around us, but it could also shed light on diseases such as depression and bipolar and anxiety disorders. In many instances, these conditions are treated with drugs that depress dopamine production. The new findings may help researchers better target the specific dopamine cells that cause individuals to misinterpret sensory cues, particularly information that could be perceived as uncertain or ambiguous.
Additional co-authors of the study include Emily Kelly and Ria Pal with URMC, Joseph Bedont with the University of Pennsylvania, Lydia Park with the State University of New York at Buffalo, and Brian Ho with Boston University. The research was funding with support from the National Institute of Mental Health and Xerox Corporation.
Mark Michaud |